Eight spontaneously arising tumors in our C3Hf/Sed mice will be studied for comparison of tumor transplantability, growth rate, mitotic index, macrophage content, lysozyme level, metastases, frequency and sites of metastases, histopathologic type, histopathologic grade. These tumors will then be evaluated for response of established tumors to local irradiation and the effectiveness of immunological manipulation of the host to modify growth of the tumor and response to radiation. Special emphasis will be placed on the use of the immunopotentiator, Corynebacterium parvum. We will determine the specific immunological reactivity against tumor following complete regression after irradiation of the fibrosarcoma and squamous cell carcinoma which were treated at 8 mm and 14 mm size (a moderate size and a very large tumor size). The interaction of C. parvum and local hyperthermia to alter responses of normal tissue to hyperthermia will be investigated. Effect of systemic alterations of pH on response of tumor and normal tissue will be evaluated.